Process of coating and treating materials having an iron base



I. I.. HERMAN. PROCESS 0F COATING AND TREATING MATERIALS HAVING AN IRONBASE. APPLICATION man MAR. 192.2.

31,430,649, mamma. OCI. 3, w22.

nucnfot Patented @cto 3, T922..

JOSEPH L. HERMAN, 0F PEURIA, LLINOTS.

PROCESS 0F COATING ANDy TREATING MATERTALS HAVEN@ AN IRON' BASE.

Application led March 6, 1922.

Be it known that l, JosnrH L. HERMAN, a citizen of the United States, aresident of Peoria, in the county of Peoria and State of lllinois, haveinvented new and useful` Improvements in Processes of Coating andTreating Materials Having an lronBase, of which the following is aspecilication.

This invention has reference to a process of coating and treatingmaterials having an iron base and particularly the coating and treatmentof wire used in the fence industry and for telephone and other purposes.

The principal object of the invention is to subject the coated materialto a simultaneous heat-treatment and annealing during' the continuousprocess of coating such material and preferably immediately upon thematerial leaving the molten coating bath in which the material isimmersed or through which the material is moving. -Such heattreatmenthas for its object an improved coating which will be more resistant toatmospheric rusting and corroding conditions than is'oi'dinarygalvanized wire, and which further will permit a heavier coated wire tobe used in wire fabricating machines without -causing the coating tocrack or Hake off, as is the case with heavily coated galvanized wirecoated by ordinary processes; the annealing of the material being forthe usual softening purposes.

The invention has for a further objectto subject the coated material toa heat-treatment o1 to a simultaneous heat-treatment and annealing in anair or oxygen free atmosphere.

The invention has for a further object to apply a heavier coating on thewire with a shorter immersion in molten zinc than is the case withordinary galvanized wire carrying the heavier coating.

A further object of the invention is to permit the use of higher speedsfor galvanizing wire than can be used under the ordinary galvanizingprocess where heavier coatings are desired and at the same time causinga heavier coating to be formed on the wire. v

This application is a companion to the application for patent filed byme on F ebruary l0, 1922, bearing Serial Number 535,660 for a process ofcoating and treating materials having an iron base. The invention hereindiffers. from that disclosed in said pending application in that theusual Serial No. 541,561.

annealing step is combined with the heattreatment and suchheat-treatment preferably takzes place in an air or oxygen freeatmosphere.

Galvanized wire which is to be used for fabricating purposes and moreparticularly that which is to be used in the manufacture of woven wirefencing must have a relatively heavy coating' of spelter in order to beable 65 to withstand atmospheric corroding conditions, and before myinvention was developed this was not possible except at a much increasedcost of production.

The universal practice for testing the relative value of spelter ongalvanized wire is 'by the so-called Preece or copper sulfate test.There are other tests, however, which are used for quantitativelydetermining the amount of spelter on galvanized wire, such as strippingthe coating in caustic soda solution; in a suitable hydrochloric acidsolution; in a solution of hydrochloric acid and antimony chloride, andin a lead acetate solution. The copper sulfate test, although so notstri ctly quantitative, is comparative when used under known conditionsof temperature and strength, and being a quick test, and one which canbe performed by any one after a little experience, has come to be theroutine testing medium for galvanized wire coatings.

At the present time there are only two (2) methods in' use whereby thesenecessary heavy zinc (spelter) coatings may be obtained by the hotprocess of galvanizing.

The first method is to pass the wire very slowly as it emerges from thegalvanlzlng bath, through finelydivided charcoal. lBy such a process asmooth, thick coating may be obtained. This method is used for makingtelephone wire. llt has serlous drawbacks, however, from an economlcstandpoint, because the wire must travel at a very slow speed, a veryhigh grade zinc must be used, and, furthermore, the coated wire can- 10onot be subjected to the action of wire-fence fabricating machineswithout havmg considerable of the zinc coating'crack or flake off theiron base. The second method 1s to cause the wire to travel atrelatively slow 105.

speeds, through a bath of molten spelter, the speed depending on thegauge of wire, the

vthickness of coating desired and the length of the molten spelter bath,and then wiping the wire by passing it between suitableA c wipers. Inother words, a wire will have a heavier galvanized coatlng, as measuredby means ,I -treater and annealer is heated all the the copper sulfatetest, the longer it remains in the molten spelter. v This latterprocess,

too, has its economic drawbacks, because of the slow speeds required,the long spelter pans necessary and consequently the lessening of thetonnage passing through a galvanizing unit in a given time.

In the accompanying drawing there is illustrated diagramatically theusual or ordinary continuous galvanizing or coating apparatus, 'exceptthe annealing furnace which is not laced as it is ordinarily, andincludes the acid bath, flux7 bath, coating or galvanizing bath, and myheattreater associated therewith, which in this instance is used as a`combined heattreater and annealer. There is also illustrated a meanswhereby an air or oxygenl free atmosphere may be maintained within mylheat-treater and annealer, wherein both ends of the heat-treate'r andannealer are sealed; one, end being submerged below the surface ofthecoating bath and the other being submerged below the surface of water,oil or some other sealing Thus when my combined heatoxygen in theconined airis soon used up and both ends being sealed no more air canenter so long as the heat is mainl tained.

My process consists preferably in treating wlre as is usual in the'ordinary contint scribed, which follows the coating step, and

" phere.

preferably in an air or oxygen free atmos- I have discovered that ifafter the wire leaves the coating bath it is subjected to a temperatureof approximately 1250O F. I not only havea superior coated wire but saidwire is also annealed. I realize that annealing per se is not new, butis new in conjunction with my heat-treatment of the coated wire. I' alsorealize'that the annealing temperature will vary for diHerent carboncontents or kinds of wire,` or whether the annealing is to relieve thestrain of bench hardening that comes from the cold working of the wire,o r whether from some other source. For example, if -a bench hardenedNo. 12gauge wire (American steel wire gauge) the carbon content of whichis approximately 0.12% -is passed through molten spelter, thetemperature of whichis approximately 870 F., for-approximately twoseconds and then through a heat-treater, preferably-a heated tube heldat approximately 1250o F. and preferably free of air or oxygen, forapproximately ten seconds, and with lor without wiping after leaving theheat-treatment, a wire is coated which will stand approximately four 65.

one minute immersons in copper sulfate;

` must be annealed.` Heretofore this step Madea@ unsalable product', andcannot be successfully used in fence fabricating machines.

What I have described for No. l2 gauge wire is also true for othergauges of wire, some of the larger` gauges such as No. 9 standingofttimes many more than four copper sulfate immersion tests. I do not,of course, limit myself to the speeds and temperatures above givenbecause I have found that I may vary the speeds by controlling `thetemperatures; for example, if I want the wire to travel at a high speed,then I use higher temperatures, and vice versa, as clearly described inmy copending application, above referred to.

Heat-treatment as employed by me has reference to such treatment as willproduce a physical or chemical change in the material undergoingtreatment. Annealing is'also a heat-treatment and refers to thesoftening of hard wire, such as bench hardened wire. It is well knownthat when wire is drawn it becomes harder after each reduction, due tophysical changes which take place within its structure. may be relievedand the v vire made soft by heating the wire to a much lower temperaturethan would be the case if the hardness was due to carbon hardness. Forexample--n a 0.12% carbon wire it is well known that in order toannealfor carbon hardness it is necessary tor heat the wire in theneighborhood of 1650o F., whereas This hardness,

heating to around 1250o F. will be suicient i to relieve the hardnesscaused by the-drawing of the wire and expressed by me asp.

bench hardness.

It is well known that hard wire 'is un-` suitable for use in many kindsof wire fabl'- For this reason the wire has taken place preceding thecoating o the wire, but in my new process, I do this sub.- sequent t`othe coating of the wire and in Lconjunction with my heat-treating. This,of course, eliminates one complete stepl in the continuous galvanizingprocess and effects considerable economies from ya cost standpoint. f

When the ywire leaves the coating bath and is not wiped or smoothed anuneven brittle coating is theresult. I therefore subject the coatedmaterial to a suitable heatcating machines.

treatment such as I have previously described. The result of thisheat-treatment is a smooth, even, pliable coating and due to the factthat the coating was not wiped there is a heavier coating on the Wirethan is the case with ordinary processes. Furthermore, when galvanizedcoatings are subjected to high temperatures in the presence of air oroxygen the zinc of they spelter burns to Zinc oxide. For this reason Ifind it preferable to exclude air or oxygen from my heat-treater.

Wire galvanized by my process has an exceptionally smooth coating evenWithout the use of Wipes. This gives me another advantage, in that Ieliminate the production of reachers which, With the ordinarygalvanizing practice are always produced and as such are valuelessexcept as scrap. Furthermore, it is not necessary for me to useexcessively long spelter pans, as I have eliminated the necessity forlong immersion of the Wire in molten spelter:

By eliminating the initial annealing step and coordinating the annealingand heattreatment after coating, I avoid the necessity of using aspecial furnace for the initial annealing and thus effect considerableeconomies over the lusual and long established process.

and continuously moving the material through the heat.

\ 3. 'Ihe process of treating un-annealed metal coated materials havingan iron base which consists in simultaneously subjecting the material toa heat-treatment and annealing in an air or oxygen free atmosphere.

4c. rlShe process of treating un-annealed metal coated materials havingan iron base which consists in simultaneously subjecting the material toa heat-treatment and annealing in an air or oxygen Jfree atmosphere, andcontinuously moving the material during such heating and annealing.

5. rIhe process of treating un-annealed metal coated materials having aniron base which consists in simultaneously subjecting the material to aheat-treatment and annealing.

6. The process of treating un-annealed metal coated materials having aniron base which consists in simultaneously subjecting the material to aheat-treatment and annealing, and continuously moving-the materialduring such heating and annealing.

7. The process of galvanizing Wire, which consists in continuouslymoving the Wire and during such movement subjecting the same, firstto amolten bath of spelter and upon leaving the bath subjecting the coatedWire to a heat-treatment in an air or oxygen free atmosphere.

8. rllhe process of galvanizing lin-annealed wire, which consists incontinuously moving the Wire and during such movement subjecting thesame, irst-to a molten bath of spelter and upon leaving the bathsubjecting the coated Wire to a simultaneous annealing andheat-treatment in an air or oxygen free atmosphere.

